DE.CM-02: The physical environment is monitored to find potentially adverse events

To meet de.cm-02: the physical environment is monitored to find potentially adverse events requirement, you must implement and operate monitoring that detects, logs, and escalates security-relevant physical conditions and access events across facilities that host or support your systems. Operationalize it by defining monitored events, assigning owners, wiring alerts into incident response, and retaining evidence that monitoring runs and exceptions are tracked. ¹

Key takeaways:

• Define what “adverse physical events” mean for your sites, assets, and threat model, then monitor them continuously or on a documented schedule. ¹
• Tie physical monitoring alerts to your cyber incident workflow, so alarms produce tickets, triage, and corrective action, not just dashboards. ¹
• Keep an audit-ready evidence bundle: scope, device/coverage inventory, alert rules, logs, reviews, and remediation records. ¹

DE.CM-02 sits in the “Detect / Continuous Monitoring” family of NIST CSF 2.0 and targets a gap many programs have: strong logical controls paired with weak visibility into the spaces where systems live. If an attacker can enter a wiring closet, tailgate into a restricted area, tamper with a network rack, or trigger an environmental condition that takes systems offline, your cybersecurity controls can fail without any “cyber” alert firing. ¹

For a Compliance Officer, CCO, or GRC lead, the fastest path to operationalizing DE.CM-02 is to treat it as a control system with (1) defined monitored events, (2) assigned responsibility across Security, Facilities, and IT, (3) alerting and escalation criteria, and (4) objective evidence that monitoring runs and is reviewed. The requirement is outcome-based, so your job is to make it auditable: a clear scope of spaces and assets, a monitoring design that matches risk, and a repeatable review cadence with tracked exceptions. ¹

Regulatory text

Requirement (excerpt): “The physical environment is monitored to find potentially adverse events.” ²
CSF reference: DE.CM-02 ³

What the operator must do: implement monitoring over facilities and physical infrastructure that could affect confidentiality, integrity, availability, safety, or resilience of systems and data; detect adverse events; and ensure events are captured and acted on through defined response paths. In practice, “monitored” means you can show: coverage (what areas), mechanisms (how you monitor), detection outputs (logs/alerts), and operational follow-through (triage, remediation, and management review). ¹

Plain-English interpretation

You need visibility into the physical conditions and physical access around the systems you rely on. Monitoring must be purposeful: it should catch events like unauthorized entry, forced doors, access outside approved hours, tampering with sensitive areas, environmental risks (smoke/water/temperature), and power anomalies that can indicate malicious activity or cause outages.

Auditors and customer assessors typically look for two things:

1. Coverage makes sense for your footprint and risk profile (headquarters, branch sites, data rooms, network closets, labs, and offsite locations you control).
2. Monitoring produces action, not just devices on walls. A camera no one reviews and a badge system that does not alert are weak evidence.

Who it applies to (entity and operational context)

This applies to organizations running a cybersecurity program under NIST CSF 2.0, including:

• Critical infrastructure operators with operational technology, control rooms, remote sites, and substations or plants. ¹
• Service organizations that host, process, or transmit customer data, including SaaS providers with offices and data rooms, and companies using colocation cages they manage. ¹
• Any enterprise with on-prem infrastructure, controlled spaces, or regulated operations where facility incidents can become security incidents. ¹

Operational contexts to explicitly scope:

• Corporate offices with sensitive functions (finance, exec, HR), especially if they contain local infrastructure.
• On-prem server rooms, network closets, and telecom demarcation points.
• Warehouses, labs, manufacturing floors, and secure storage where assets or media exist.
• Remote/branch sites with minimal staffing.
• Third-party facilities you do not operate (public cloud, many colos): you still need monitoring assurance, but evidence often comes via third-party reports and your vendor management process rather than your own sensors.

What you actually need to do (step-by-step)

1) Set scope: spaces, assets, and “adverse events”

• Build a physical security monitoring scope list: buildings, floors, restricted rooms, cages, and critical infrastructure locations.
• Identify “crown jewel” physical assets in those spaces: core network gear, identity systems, backup media, endpoint staging areas, production equipment.
• Define potentially adverse events relevant to your business. Use an event taxonomy that maps cleanly to tickets and reporting, for example:
  • Unauthorized entry attempt, tailgating suspected, door forced/held open
  • Access granted outside approved hours for restricted areas
  • Visitor policy breach (unescorted visitor in controlled space)
  • Environmental threshold breach (smoke, water, temperature/humidity)
  • Power anomalies (UPS on battery, generator fail, unexpected shutoff)
  • Tamper events (rack door open, panel removed, sensor offline)

Deliverable: a one-page “DE.CM-02 monitoring outcomes” statement with owners and measurable indicators. ¹

2) Assign ownership across teams (and document it)

Physical monitoring fails in handoffs. Put names to roles:

• Facilities/Site Security: cameras, door sensors, alarms, environmental sensors, guard procedures
• IT/SecOps: correlation into incident workflow, logging, alert tuning, response playbooks
• GRC: control definition, evidence collection, exception tracking, reporting

Use a RACI that covers: sensor health, alert triage, incident declaration, and maintenance windows.

3) Implement monitoring mechanisms and alerting pathways

Pick mechanisms appropriate to your footprint; you are not required to deploy every device type, but you must cover credible risks.

• Access control monitoring: badge logs, forced-door alarms, door-held-open timers, anti-passback where appropriate.
• Video surveillance monitoring: camera coverage of entrances and restricted areas; documented review triggers (for example, review footage tied to an access anomaly).
• Environmental monitoring: smoke/water/temperature sensors in server rooms and critical closets; alerts to on-call.
• Power monitoring: UPS and generator status alerts; tie “on battery” and “runtime low” to incident workflow.
• Tamper and health monitoring: alerts when sensors/cameras go offline, are obstructed, or lose power.

Operational requirement: alerts must route to a monitored queue (SOC, on-call rotation, security desk) with defined severity and response times you set internally.

4) Integrate with incident response and ticketing

Make physical alerts actionable:

• Create an “Physical Security Event” ticket type (or equivalent).
• Define triage steps: verify alert source, validate against approved access, dispatch onsite check, preserve footage/logs, escalate to cyber incident if indicators suggest tampering.
• Add playbooks for common scenarios: forced entry, after-hours access, water leak in data room, camera outage.

A common exam hangup: an assessor asks, “Show me one example where a physical alert generated a ticket and was closed with corrective action.” Have that ready.

5) Run control performance reviews (and track exceptions)

Operate the control like any detection control:

• Review metrics and exceptions on a repeating cadence you define, such as:
  • Coverage gaps (spaces without sensors)
  • Devices offline and mean time to restore
  • Alert volumes and false positives
  • After-hours access exceptions and approvals
• Document decisions: accepted risk, remediation plans, due dates, and owners. ¹

6) Extend to third parties through assurance, not guesswork

For locations you do not control (cloud, many colos, managed offices), you still need a monitoring story:

• Contract language for physical security and environmental controls.
• Evidence via third-party assurance packages where available (reports, attestations, customer audit letters).
• Clear delineation: “We monitor our offices and cages; the provider monitors building perimeter and core plant; we review provider evidence during periodic vendor reviews.”

Daydream can help here by structuring third-party due diligence requests so you can map provider evidence back to DE.CM-02 without chasing ad hoc screenshots.

Required evidence and artifacts to retain

Keep an “evidence bundle” that a non-expert can review quickly:

• Scope & ownership
  • Physical monitoring scope list (sites/areas) and RACI
  • Definition of “adverse events” and alert severity criteria
• System inventory and configuration
  • Inventory of monitoring systems (ACS, cameras, environmental sensors, UPS monitoring)
  • Alert routing configuration (who receives what)
  • Maintenance/inspection records for critical sensors (where applicable)
• Operational records
  • Sample logs (badge events, forced-door alarms, environmental alerts)
  • Tickets/cases showing triage, investigation notes, resolution, corrective action
  • Review meeting notes or monthly control review sign-off with exceptions and remediation tracking ¹
• Exceptions
  • Approved compensating controls for sites that cannot meet baseline monitoring
  • Risk acceptance documentation with time bounds and owner

Common exam/audit questions and hangups

• “Which facilities are in scope, and why?” Expect scrutiny on remote sites and small closets.
• “Show how you detect after-hours access to restricted areas.” If you only store badge logs, that is usually weak unless you can show review and escalation.
• “What happens when a camera or sensor goes offline?” Have a defined response and evidence of follow-up.
• “How do physical events feed incident response?” Auditors want to see tickets, not narratives.
• “How do you monitor physical security at third-party data centers/cloud?” Be ready with contracts and assurance evidence, plus your review cadence.

Frequent implementation mistakes and how to avoid them

1. Monitoring without response ownership. Fix: define an on-call and ticket queue, and test it with a tabletop.
2. “We have cameras” as the control. Fix: document what triggers review (access anomalies, incidents) and retain examples.
3. No device health monitoring. Fix: alert when sensors go offline; track restoration time.
4. Scope drift. Fix: tie scope to asset inventory and site lifecycle (new offices, new cages).
5. Third-party blind spot. Fix: add physical monitoring assurances to third-party reviews, and store evidence with the vendor record.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so you should treat DE.CM-02 primarily as a defensibility and resilience control under the NIST CSF 2.0 framework. The risk is practical: physical intrusion and environmental failures often bypass logical defenses and can turn into reportable incidents, outages, or data exposure depending on what systems are affected. ¹

Practical 30/60/90-day execution plan

First 30 days (stabilize scope and accountability)

• Publish DE.CM-02 scope: sites, restricted areas, critical closets.
• Create the adverse event taxonomy and severity criteria.
• Assign RACI across Facilities, IT/SecOps, and GRC.
• Confirm where alerts land today; eliminate “email to nobody” paths.
• Stand up an evidence folder and start capturing baseline artifacts. ¹

Next 60 days (wire to operations and prove it works)

• Integrate alerts into ticketing (or standardize the process if already integrated).
• Implement or tune alerts for top adverse events: forced door, after-hours restricted access, environmental thresholds, UPS on battery.
• Add device health alerts for monitoring components.
• Run a control performance review; log exceptions with remediation dates and owners. ¹

Next 90 days (reduce gaps and make it auditable)

• Close highest-risk coverage gaps (or document compensating controls and risk acceptance).
• Perform a test: trigger a benign physical alert and verify ticketing, response, and evidence capture end-to-end.
• Mature third-party assurance mapping for facilities you do not control, and store evidence in your third-party risk files.
• Produce a concise quarterly DE.CM-02 report for leadership: coverage, exceptions, and remediation progress. ¹

Frequently Asked Questions

Does DE.CM-02 require 24/7 live camera monitoring?

The requirement says the physical environment is monitored, not that every camera has continuous live review. Define which events require real-time response versus retrospective review, then retain evidence that the process runs. ¹

What counts as a “potentially adverse event”?

Any physical condition or access event that could harm confidentiality, integrity, availability, or safety for in-scope systems. Document your event list and why it matches your footprint and threat model. ¹

We are mostly cloud-hosted. How do we meet this requirement?

Scope your own offices and any spaces where staff handle sensitive assets (endpoints, paper records, backups). For cloud facilities, rely on third-party assurance and contract requirements, then document your review and evidence retention. ¹

How do we show auditors this control is operating?

Provide an evidence bundle with alert configurations, sample logs, tickets showing triage and closure, and periodic review notes with tracked exceptions and remediation. ¹

Who should own DE.CM-02: Facilities or Security?

Split ownership. Facilities or site security usually owns sensors and access systems; Security/SecOps owns alert triage integration and escalation into incident response; GRC owns control definition and evidence. Put it in a RACI and enforce it. ¹

What if a small branch office cannot support the same monitoring as HQ?

Document a risk-based exception with compensating controls (for example, restricted equipment storage, tamper seals, periodic inspections, or a different monitoring method). Track remediation or acceptance decisions with an owner and review date. ¹

Footnotes

1. NIST CSF 2.0

2. NIST CSWP 29

3. NIST CSF 1.1 to 2.0 Core Transition Changes